In the fields of biology and medicine, there is often a need for high throughput analysis and sorting of particles.
One well known technique for analyzing and sorting particles is droplet deflection. See, for example, U.S. Pat. No. 6,372,506, which is incorporated by reference, herein, in its entirety. In droplet deflection, a stream of suspended particles is broken into individual droplets, for example, using a piezoelectric mechanism. At the point of droplet formation, an electrical charging element is used to selectively charge each droplet. The charged droplet then free falls through an electrostatic field, which deflects the charged droplet into one of a plurality of receiving containers.
Another technique for analyzing and sorting particles involves utilizing switching or pressure mechanisms to divert a volume of fluid containing a particle into a selected branch channel of a flow-path defined on a microfluidic chip. See, for example, U.S. Pat. No. 6,808,075, which is incorporated by reference, herein, in its entirety.
In a microfluidic system, such as a droplet sorter or a microfluidic chip, an optical system may be used for monitoring, analyzing and/or detecting particles and/or liquids flowing through the system, for example, in a flow-path such as defined by a microchannel or by stream of droplets. Such an optical system for illuminating a flow-path of a microfluidic system may be useful, for example, in a particle sorting system that sorts particles based on one or more particle characteristics as detected using the optical system.